I try to read the result of the query and discover if some of the columns is empty This is a way I started:
SqlDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
{
rdr["ColumnName"]; // how do I know if it has a value or empty
}
I thought to do :
dr[4].ToString() == String.Empty
It makes a needed work, but I don`t like this (it is a hack rather than solution) can you advise me how do I do it correctly and elegantly?
Empty does not exists for int values and what is correct when working with databases is use Null which is the only true "Empty".
SqlDataReader rdr = cmd.ExecuteReader();
int colIndex = read.GetOrdinal("MyColumnName");
while (rdr.Read())
{
// [true | false] your validation goes here!;
if (rdr.IsDBNull(colIndex)){
//value is null
}
}
Please note that if you want use 0, "" or 1/1/1900 as empty values those will require a custom treatment.
This is how I do it
string UserInitialssql = rdr.IsDBNull(2) ? String.Empty : rdr.GetString(2);
If it is Int
Int32? i = rdr.IsDBNull(2) ? (Int32?)null : rdr2.GetInt32(2);
Another possibility is to use nullable types. e.g.:
SqlDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
{
int? someNumber = rdr["ColumnName"] as int?;
if (someNumber == null)
// was NULL in database
else
// use someNumber.Value to get int
}
